1. Field of the Invention
The described technology relates generally to a design for a rechargeable battery capable of discharging an internal gas when swelling occurs.
2. Description of the Related Art
Unlike a primary battery, a rechargeable battery is capable of being charged and discharged. Due to such an advantage, the rechargeable battery has been widely used in electronic devices such as cellular phones, laptop computers, and camcorders. For example, a lithium rechargeable battery has been widely used because of its high operation voltage and high energy density per unit weight.
The lithium rechargeable battery is manufactured in various shapes. For example, the lithium rechargeable battery can be manufactured to have a cylindrical shape, a rectangular shape or a pouch shape. The pouch-shaped rechargeable battery includes an electrode assembly and a pouch exterior material. The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator. The pouch exterior material accommodates the electrode assembly and electrolyte solution therein.
The rechargeable battery is charged and discharged through interaction of lithium ions between the positive electrode plate and the negative electrode plate. In the pouch-shaped rechargeable battery, an overcharge condition, an over-discharge condition, an internal electric short condition, and an overheating condition cause an internal temperature of the pouch exterior material to increase and cause an internal gas pressure to rise, to excessive levels. Due to such gas pressure, a swelling phenomenon of the pouch exterior material occurs. The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that is not prior art as per 35 U.S.C. §102.